Combined identifying granuloma and biopsy culture is useful for diagnosing intestinal tuberculosis

Differential diagnosis of intestinal tuberculosis (ITB) and inflammatory bowel disease (IBD) can be difficult, but many gastroenterologists may only perform biopsy for pathology and their own experience. This study aimed to identify optimal sample collection and pathogen detection methods for diagnosing ITB.

A cohort of 182 patients (50 had ITB and 132 had IBD or other colonic diseases) who underwent colonoscopy was analyzed. Sensitivity of acid-fast bacilli (AFB), culture, polymerase chain reaction (PCR), and granuloma pathology on hematoxylin and eosin stain for diagnosing ITB were compared in relation to biopsy, endoscopic aspirated intestinal fluid, or standard stool evaluations. We also evaluated which combination offered the highest yield to diagnose intestinal tuberculosis in addition to granuloma pathology.

Between ITB and non-ITB, no significant differences were observed in age, sex, and nationality. In biopsy analysis, sensitivity was as follows: culture (50%), AFB (38%), PCR (25%), granuloma pathology (51%), and caseous granuloma (8.2%), while specificity of granuloma pathology was low (80%), compared to other tests. In intestinal fluid analysis, sensitivity was as follows: culture (46%), AFB (42%), and PCR (35%). In standard stool analysis, sensitivity was as follows: culture (47%), AFB (37%), and PCR (23%). Granuloma pathology plus biopsy culture offered the highest combination sensitivity (77 %), significantly (P < 0.01) higher than that for granuloma pathology alone (51%).

When encountering suspected intestinal tuberculosis or IBD on colonoscopy, biopsy culture is recommended in addition to pathological assessment of granuloma. This diagnostic strategy will lead to accurate differential diagnosis of colonic disease, facilitating appropriate treatment.